Effects of Climate Stress on Plants
Every plant is adapted to environmental conditions which it requires to live. When these conditions aren’t met plants experience what is known as “environmental stress”. This can be triggered by extreme climatic conditions like droughts, floods, wind, and extreme temperatures. Environmental stress not only inhibits plant growth but often leads to other health consequences such as tissue damage or sensitivity to pests and diseases.
Drought stress occurs when the plant does not have enough water available for conducting photosynthesis.
+ At the beginning stages plants will slow down their photosynthetic activity and close their stomata to reduce transpiration. This results in slower growth.
+ Extended drought stress can cause the plants to begin losing their leaves and even self-pruning branches.
+ Some plants may lose all their above ground vegetation and resprout from their roots once conditions are adequate.
+ Extensive drought stress can result in death.
Excessive heat often has similar symptoms to drought stress but is distinct in several ways.
+ Even if the plant has enough water, too much heat can impair the photosynthetic functioning of plant cells.
+ Excessive heat will speed up the degradation of chlorophyll causing the plant's foliage to look “burnt”. Over time this may result in the loss of foliage.
+ Some plants begin to bolt under heat stress, causing them to flower before they’ve achieved their desired vegetative growth.
+ Heat stress can occur because of high air temperatures but also due to high soil temperatures.
Cold and Frost Stress
Cold weather can be just as detrimental to plants as hot weather.
+ Plants not suited to cold weather slow their metabolic processes and may not be able to conduct photosynthesis when temperatures drop. This can result in slow growth and browning of foliage.
+ Frost can cause serious damage to plants that are not properly adapted. When temperatures are below freezing plant cells will freeze and burst resulting in instant cell-death.
+ Plants adapted to cold temperatures produce secondary compounds that help reduce negative effects of freezing. These may take time to produce and plants are better adapted when temperatures slowly drop as opposed to having a sudden drop.
Stress From Excessive Soil Moisture
Most plants are not adapted to live in saturated or waterlogged soils. The exception to this are aquatic plants who have developed specific methods to counteract the challenges of these conditions.
+ One of the biggest issues with excessive soil moisture is that it creates anoxic conditions where oxygen is limited. Since plant roots require oxygen for their metabolic process, the lack of oxygen means plant cells stop working. This can result in cell death, tissue damage, and attract fungi/bacteria which may then infect the root system.
+ Excessive soil moisture will also alter the biological communities in the soil and promote potentially infectious and harmful microbiology.
+ Wind stress can cause physical damage to plants. This means broken limbs and the removal of foliage. Plants exposed to winds throughout their lives will have tougher stems that will be more resistant.
+ Wind stress can also dry out the soil and leaves quicker if there is a lack of moisture.
+ Wind-chill does not affect plants since they do not produce their own heat, but the drying effect can cause more stress during already stressful environmental conditions.